Arena Pharmaceuticals has completed a phase Ib clinical trial for APD811, an investigational oral prostacyclin (IP) receptor agonist intended for the treatment of pulmonary arterial hypertension (PAH). The company plans to initiate a phase II clinical trial for APD811 in the first quarter of 2014.

This randomized, double-blind and placebo-controlled phase Ib clinical trial evaluated the safety, tolerability and pharmacokinetics of multiple-ascending doses of APD811. Arena previously evaluated single-ascending doses of APD811 in a phase Ia clinical trial.

In the phase Ib clinical trial, 40 healthy volunteers received APD811 and 15 received placebo, and the safety profile of APD811 was characteristic of IP receptor agonists. No serious adverse events were observed, and the most frequent treatment-emergent adverse events were headache, nausea and jaw pain. The results of the phase I program led to the decision to proceed with phase II development of APD811, which will include further exploration of dosing regimens in PAH patients.